Antioxidant enzyme expression in health and disease: effects of exercise and hypertension

Physical activity for cognitive health promotion: An overview of the underlying neurobiological mechanisms

Physical activity is one of the modifiable factors of cognitive decline and dementia with the strongest evidence. Although many influential reviews have illustrated the neurobiological mechanisms of the cognitive benefits of physical activity, none of them have linked the neurobiological mechanisms to normal exercise physiology to help the readers gain a more advanced, comprehensive understanding of the phenomenon. In this review, we address this issue and provide a synthesis of the literature by focusing on five most studied neurobiological mechanisms. We show that the body's adaptations to enhance exercise performance also benefit the brain and contribute to improved cognition. Specifically, these adaptations include, 1), the release of growth factors that are essential for the development and growth of neurons and for neurogenesis and angiogenesis, 2), the production of lactate that provides energy to the brain and is involved in the synthesis of glutamate and the maintenance of long-term potentiation, 3), the release of anti-inflammatory cytokines that reduce neuroinflammation, 4), the increase in mitochondrial biogenesis and antioxidant enzyme activity that reduce oxidative stress, and 5), the release of neurotransmitters such as dopamine and 5-HT that regulate neurogenesis and modulate cognition. We also discussed several issues relevant for prescribing physical activity, including what intensity and mode of physical activity brings the most cognitive benefits, based on their influence on the above five neurobiological mechanisms. We hope this review helps readers gain a general understanding of the state-of-the-art knowledge on the neurobiological mechanisms of the cognitive benefits of physical activity and guide them in designing new studies to further advance the field.

Method for Determining the Body's Level of Protection According to Oxidant Status in Assessing the Influence of Industrial Risk Factors on Health

This work aims at improving the quality of health assessments, specifically under the influence of occupational risk factors. For this purpose, additional informative indicators are utilized in prognostic and diagnostic models. The models are used to characterize the level of body protection based on oxidative status. A quantitative method is proposed to assess the body's level of protection by means of the levels of lipid peroxidation and antioxidant activity, which characterize the body's oxidative status. A mechanism is developed for integrating the proposed method into prognostic and diagnostic decision rules. The developed rules are in the form of mathematical models used to synthesize hybrid fuzzy decision rules, which are then used to quantify the level of body protection (LBP) against external risk factors, based on the use of protection level functions in terms of lipid peroxidation and antioxidant activity. A mechanism for embedding LBP into predictive and diagnostic decision rules has been proposed. The proposed method is used to predict the occurrence and development of coronary heart disease in railroad locomotive drivers. It was found that to improve the predicting and diagnosing of diseases caused by external pathogenic factors, quantitative assessments of LBP, determined by oxidative status, can be implemented. It has been established that the use of the protection level indicator in predictive decision rules makes it possible to increase the efficiency of the prediction while simultaneously increasing its accuracy.

The effect of natural infection with different Leptospira interrogans serovars on oxidative stress biomarkers and acute-phase responses in horses and cattle

Leptospirosis is one of the important zoonotic bacterial diseases with a worldwide distribution that is often subclinical. We aimed to investigate the oxidant/antioxidant balance and acute-phase response in naturally infected horses and cattle with Leptospira interrogans. A total of 600 serum samples from horses and cattle were examined for L. interrogans antibodies using the microscopic agglutination test to determine anti-Leptospira IgG antibodies against a panel of eight important Leptospira antigens in Iran. Then, serum total antioxidant capacity, catalase, glutathione peroxidase, and malondialdehyde activities, and nitric oxide, total protein, serum amyloid A, haptoglobin, and albumin concentrations were measured in seropositive and seronegative samples. Serum catalase activities and malondialdehyde, serum amyloid A, and haptoglobin ‌concentrations in seropositive cattle and horses were significantly higher (P < .05) than in those that were seronegative. Antibody titers increased from 1:100 to ≥ 1:200 in cattle with L. interrogans infection, resulting in a decrease in the serum total antioxidant capacity (P < .05), an increase in serum glutathione peroxidase (P < .01) activity and nitric oxide (P < .05) , serum amyloid A (P < .01), and haptoglobin (P < .05) concentrations. Following the increase in the agglutinating antibody titers in horses infected with L. interrogans, the serum total antioxidant capacity (P < .01) decreased, and serum nitric oxide (P < .05), malondialdehyde (P < .05), and serum amyloid A (P < .01) concentrations were increased. In this study, horses and cattle had extensive changes in oxidant/antioxidant equilibrium and acute-phase protein concentrations when infected with L. interrogans. We also demonstrated a direct link between antibody titers and the type of leptospiral serovar using serum oxidative and inflammatory markers.

Evaluation of the Partial Replacement of Dietary Fish Meal With Fermented or Untreated Soybean Meal in Juvenile Silver Barb, Barbonymus gonionotus

Fish meal (FM) has excellent protein and lipid profile. However, FM is losing its acceptability and substituted with plant protein due to FM has high price, high demand, and sustainability issues in global aquaculture production. In this study, experimental diets were prepared by substituting FM with fermented soybean meal (FSM) or normal and untreated soybean meal (SM) to assess the effects on growth, hematology, innate immunity, gut physiology, and digestive enzyme activities in juvenile silver barb, Barbonymus gonionotus. Five diets, that is, 40% FM (FM 40), 20% FM + 20% FSM (FM 20 + FSM 20), 20% FM + 20% SM (FM 20 + SM 20), 40% FSM (FSM 40), and 40% SM (SM 40) were fed to the fish two times daily for 90 days. After 90 days of feeding trial, FM 40, FM 20 + FSM 20, and FM 20 + SM 20 diet groups showed significantly higher weight gain (WG) and specific growth rate (SGR) compared to the FSM 40 and SM 40 diets. Hepatosomatic index (HSI) and viscerosomatic index (VSI) were significantly higher in fish fed with the FSM 40 and SM 40 diets than those of fish fed with the FM 40 diet. Hematocrit, hemoglobin, and erythrocyte count were significantly lower in fish fed with the SM 40 diet compared to fish fed with the FM 40 and FM 20 + FSM 20 diets. Superoxide dismutase and catalase activities in the liver were significantly higher in fish fed with the SM 40 diet compared to fish fed with the FM 40 diet. However, serum thiobarbituric acid reactive substances in fish fed with the experimental diets were unaltered. Fish showed significant reduction of villus height (Vh) in the anterior and posterior intestine of fish fed with the FSM 40 and SM 40 diets, whereas muscular thickness was opposite to the findings of Vh. Digestive enzyme activities in intestine were significantly higher in fish fed with the FM 40 diet compared to those in the SM 40 diet. The results of the present study revealed that the 50% of FM can be replaced by FSM or SM as a source of protein without affecting the growth of juvenile silver barb.

Immunological Responses and the Antioxidant Status in African Catfish (Clarias gariepinus) Following Replacement of Dietary Fish Meal with Plant Protein

Simple Summary

The price of feed ingredients is one of the most important and most costly constraints facing the aquaculture industry, and fishmeal is one of the most important and most expensive of these ingredients. As a result, recent research has focused on the use of alternative low-cost feed ingredients that are less reliant on fishmeal. Therefore, there has been considerable interest in the use of various types of plant protein (PP) meals in aquafeeds (soybean and sunflower meal). This study reveals that soybean and sunflower meal with methionine and lysine supplementation can be used on a larger scale in the aquafeed industry as substitutes of up to 50% of fishmeal.

Abstract

African catfish (Clarias gariepinus) were subjected to a 30-day feeding trial to determine the appropriateness of using plant protein (PP) (soybean and sunflower meal) as a fishmeal (FM) replacement in the diet and its effects on immune status, antioxidant activity, pituitary adenylate cyclase-activating polypeptide (PACAP) gene expression, and disease resistance. A total of 150 C. gariepinus (51.01 ± 0.34 g) were randomly distributed among five groups in triplicate. Five experimental diets were formulated to replace 0 (control), 33.5, 50, 66.5, and 100% FM with soybean and sunflower meal to form the experimental diets (R0, R33.5, R50, R66.5, and R100, respectively). After 30 days, the diet containing PP for FM had no significant impact on total, and differential leukocyte counts determined at the end of the feeding period. The total globulin concentration showed significantly greater differences in the following order R0 > R33.5 > R50 > R66.5 > R100. The R0 group had the highest concentration of serum γ-globulin, while R100 had the lowest concentration. The antioxidant status complements 3 (C3), lysozyme activity (LYZ), and antiprotease activity were not significantly different between R0, R33.5, and R50 groups, while they were significantly lower in R100. The serum nitric oxide activity (NO) exhibited significantly greater differences in the following order R0 > R33.5 > R50 > R66.5 > R100. PACAP was significantly higher in the R33.5 group. The highest cumulative mortality caused by Aeromonas sobria was recorded in the R100 group (60%) and the lowest in the R0 group (30%). In conclusion, the results indicate that the immunological responses and antioxidant status of C. gariepinus were not affected when they consumed a diet with FM replaced by up to 50% with PP (SBM and SFM) with methionine and lysine supplementation, but total globulin, NO, and cumulative mortality were impaired with a diet containing a 100% FM replacement.

Aerobic exercise modulates cardiac NAD(P)H oxidase and the NRF2/KEAP1 pathway in a mouse model of chronic fructose consumption

The present study investigated the effects of exercise on the cardiac nuclear factor (erythroid-derived 2) factor 2 (NRF2)/Kelch-like ECH-associated protein 1 (KEAP1) pathway in an experimental model of chronic fructose consumption. Male C57BL/6 mice were assigned to Control, Fructose (20% fructose in drinking water), Exercise (treadmill exercise at moderate intensity), and Fructose + Exercise groups ( n = 10). After 12 wk, the energy intake and body weight in the groups were similar. Maximum exercise testing, resting energy expenditure, resting oxygen consumption, and carbon dioxide production increased in the exercise groups (Exercise and Fructose + Exercise vs. Control and Fructose groups, P < 0.05). Chronic fructose intake induced circulating hypercholesterolemia, hypertriglyceridemia, and hyperleptinemia and increased white adipose tissue depots, with no changes in blood pressure. This metabolic environment increased circulating IL-6, IL-1β, IL-10, cardiac hypertrophy, and cardiac NF-κB-p65 and TNF-α expression, which were reduced by exercise ( P < 0.05). Cardiac ANG II type 1 receptor and NAD(P)H oxidase 2 (NOX2) were increased by fructose intake and exercise decreased this response ( P < 0.05). Exercise increased the cardiac expression of the NRF2-to-KEAP1 ratio and phase II antioxidants in fructose-fed mice ( P < 0.05). NOX4, glutathione reductase, and catalase protein expression were similar between the groups. These findings suggest that exercise confers modulatory cardiac effects, improving antioxidant defenses through the NRF2/KEAP1 pathway and decreasing oxidative stress, representing a potential nonpharmacological approach to protect against fructose-induced cardiometabolic diseases.

NEW & NOTEWORTHY This is the first study to evaluate the cardiac modulation of NAD(P)H oxidase (NOX), the NRF2/Kelch-like ECH-associated protein 1 pathway (KEAP), and the thioredoxin (TRX1) system through exercise in the presence of moderate fructose intake. We demonstrated a novel mechanism by which exercise improves cardiac antioxidant defenses in an experimental model of chronic fructose intake, which involves NRF2-to-KEAP1 ratio modulation, enhancing the local phase II antioxidants hemoxygenase-1, thioredoxin reductase (TXNRD1), and peroxiredoxin1B (PDRX1), and inhibiting cardiac NOX2 overexpression.

Effects of replacing fish meal with soybean meal on growth performance, feed utilization and physiological status of juvenile obscure puffer, Takifugu obscurus

An 8-week feeding trial was conducted to evaluate the growth performance, feed utilization and physiological status of obscure puffer, Takifugu obscurus (13.03 ± 0.14 g) fed diets in which fish meal (FM) was replaced with various levels of dehulled and defatted soybean meal (SBM): 0% (SBM0), 15% (SBM15), 30% (SBM30), 45% (SBM45), 60% (SBM60) and 75% (SBM75). No significant differences were observed in weight gain and specific growth rate (SGR) of fish when FM replacement level was lower than 30%, and the broken-line model of SGR showed the maximum replacement level was 40%. Fish fed the SBM-containing diets had a lower red blood cell value compared to the control. The hemoglobin and methemoglobin values showed a declining tendency as dietary SBM level increased. Plasma triacylglycerol, cholesterol and low-density lipoprotein cholesterol levels also showed a decreasing trend that was associated with the reduced crude lipid content of whole body as dietary SBM level increased. The activities of alanine aminotransferase and aspartate aminotransferase in fish fed the SBM-containing diets were all higher than those fed the control diet while glutathione peroxidase and catalase activities were lower than the control group. Results indicated that up to 40% FM protein, based on the broken-line analysis of SGR, can be replaced with SBM in diet for obscure puffer juveniles with supplemental lysine, methionine and taurine.

Phoenix Dan Cong Tea: An Oolong Tea variety with promising antioxidant and in vitro anticancer activity

BACKGROUND

Phoenix Dan Cong tea is an Oolong tea produced in Chaozhou, China. Nowaday, the experimental studies on the benefical effects of the Phoenix Dan Cong tea are rare.

OBJECTIVE

The objective of this study was to comprehensively evaluate the activity of Phoenix Dan Cong tea aqueous extract (PDCe).

METHODS

We used a series of evaluation methods in the present study to achieve an in-depth understanding and evaluation of the antioxidant and antitumor activity of PDCe.

RESULTS

High-performance liquid chromatography (HPLC) studies have indicated that PDCe is rich in catechins such as gallocatechin (GC), epigallocatechin (EGCG) and epicatechin gallate (ECG), with sparse amounts of theaflavins. We discovered that PDCe scavenges ABTS•+ and DPPH• free radicals in a dose-dependent manner. In addition, PDCe can significantly induce apoptosis of MDA-MB231 cells, mainly through the death-receptor-mediated extrinsic apoptotic pathway. Internalized PDCe can not only downregulate intracellular reactive oxygen species levels but also induce oxidative damage to mitochondria in MDA-MB231 cells.

CONCLUSIONS

Phoenix Dan Cong tea may act as a substitute for natural antioxidants and as a promising anticancer agent due to its protective effect on human health.

Association between the circulating leptin levels and the biomarkers of oxidative stress and inflammation among Iranian overweight and obese adults

Background: Oxidative stress in obese people is an important pathogenic mechanism of an obesity-associated metabolic syndrome. We evaluated the association between circulating leptin levels with biomarkers of oxidative stress in overweight and obese participants.

Methods: This study was performed on 189 overweight and obese people aged 18-60 years old. Serum leptin, superoxide dismutase (SOD), high-sensitivity C-reactive protein (hs-CRP), homocysteine (Hcy), thiobarbituric acid reactive substances (TBARS) and amyloid A (SAA) concentrations were measured. Pearson correlation and multiple linear regressions were used to assess the relationships.

Results: We found that among the biomarkers of oxidative stress and inflammation in participants, serum hs-CRP and SAA were positively correlated with BMI (β=0.003, P<0.001 and β=7.83, P<0.001, respectively). This relationship remained significant even after controlling other oxidative stress and inflammatory indicators (β=0.003, p<0.001 for hs-CRP), but this association disappeared for SAA. In addition, serum hs-CRP was positively correlated with leptin (β=0.001, p=0.003). Regression analysis showed that there was no association between serum Hcy, SAA, TBARS and SOD with serum leptin concentrations

Conclusion: Overall, the current study demonstrated that serum hs-CRP and SAA levels were independently correlated with BMI. Furthermore, serum hs-CRP was positively correlated with leptin. Focusing on such strategies may lead to promises for alleviating obesity and its co-morbidities.

Antioxidant defenses of Onychostoma macrolepis in response to thermal stress: Insight from mRNA expression and activity of superoxide dismutase and catalase

Onychostoma macrolepis has becoming an endangered fish species in China, which population gradually declined in the past few decades due to the changing environment including elevated water temperature resulted from adverse weather events. The present study determined antioxidant defenses of O. macrolepis in response to thermal stress, aiming to understand the role of antioxidant system in adaptation of thermal stress for O. macrolepis. Experimental fish which were acclimated at 24 °C were stressed at 30 °C for 0 h, 1 h, 3 h, 6 h, 12 h, 24 h and 48 h, respectively. Change in mRNA expression of Cu/Zn superoxide dismutase (Cu/Zn-SOD) and catalase (CAT) and activity of SOD and CAT of the experimental fish with different stress time were determined. We cloned the full-length cDNA of Cu/Zn-SOD and CAT by means of RACE method, and analyzed their molecular characterization and tissue distribution. We discovered that the mRNA expression of the Cu/Zn-SOD in heart, liver, spleen, gill, intestine and the CAT in heart, liver, spleen, kidney, intestine and muscle of O. macrolepis significantly increased when water temperature increased from 24 °C to 30 °C, indicating a sensitive response of mRNA expression of Cu/Zn-SOD and CAT to the thermal stress. Moreover, the mRNA expression of the Cu/Zn-SOD and CAT were varied in different tissues, indicating different sensitivity of the tissues in response to thermal stress. Activity of the SOD in serum of O. macrolepis gradually increased from 1 h to 12 h sampling time, but significantly decreased at 24 h sampling time, compared to that of 0 h sampling time. And activity of the CAT in serum of O. macrolepis significantly decreased from 1 h to 12 h sampling time, and did not changed significantly at 24 h and 48 h sampling time, compared to that of 0 h sampling time. As such, MDA contents in the serum of O. macrolepis significantly decreased from 1 h to 6 h sampling time, but significantly increased at 12 h and 24 h sampling time, compared to that of 0 h sampling time. In summary, antioxidant system of the O. macrolepis can quickly response to short term thermal stress at 30 °C in form of both the mRNA expression of Cu/Zn-SOD and CAT and the activity of SOD and CAT, and consequently enhance the antioxidant defenses of O. macrolepis. However, thermal stress at 30 °C for 12 h-24 h seems to lead to oxidative damage of the O. macrolepis.

Quality and antioxidant response of gilthead seabream (Sparus aurata L.) to dietary supplements of fenugreek (Trigonella foenum graecum) alone or combined with probiotic strains

The present study was conducted to determine the potential effect of the dietary intake of fenugreek (Trigonella foenum graecum) seeds alone or in combination with Bacillus licheniformis, Lactobacillus plantarum or B. subtilis on gilthead seabream quality and antioxidant response after 2 and 3 weeks of experimental feeding. The results showed that the supplements did not affect the percentage of the fatty acid profiles of muscle, demonstrating that all the additives tested can be administrated without any negative effect on biochemical composition and quality of gilthead seabream. The quantification of thiobarbituric acid reactive substances in muscle demonstrated the significant beneficial effect of the experimental diets compared with the control one. Besides, an increase in superoxide dismutase and catalase in liver was recorded after 3 weeks of administration of experimental diets. Furthermore, real time qPCR revealed that dietary supplementation with FEBS significantly enhances the expression of scavenging enzymes, such as cat and gr genes in the liver after 3 weeks. The findings suggest that the administration of fenugreek supplement alone or combined with probiotic strains could be considered as a good source of natural antioxidants and as a functional aquafeed ingredient for gilthead seabream.

Nutritional Status as the Key Modulator of Antioxidant Responses Induced by High Environmental Ammonia and Salinity Stress in European Sea Bass (Dicentrarchus labrax)

Salinity fluctuation is one of the main factors affecting the overall fitness of marine fish. In addition, water borne ammonia may occur simultaneously with salinity stress. Additionally, under such stressful circumstances, fish may encounter food deprivation. The physiological and ion-osmo regulatory adaptive capacities to cope with all these stressors alone or in combination are extensively addressed in fish. To date, studies revealing the modulation of antioxidant potential as compensatory response to multiple stressors are rather lacking. Therefore, the present work evaluated the individual and combined effects of salinity challenge, ammonia toxicity and nutritional status on oxidative stress and antioxidant status in a marine teleost, European sea bass (Dicentrarchus labrax). Fish were acclimated to normal seawater (32 ppt), to brackish water (20 ppt and 10 ppt) and to hypo-saline water (2.5 ppt). Following acclimation to different salinities for two weeks, fish were exposed to high environmental ammonia (HEA, 20 mg/L representing 50% of 96h LC₅₀ value for ammonia) for 12 h, 48 h, 84 h and 180 h, and were either fed (2% body weight) or fasted (unfed for 7 days prior to HEA exposure). Results show that in response to decreasing salinities, oxidative stress indices such as xanthine oxidase activity, levels of hydrogen peroxide (H₂O₂) and lipid peroxidation (malondialdehyde, MDA) increased in the hepatic tissue of fasted fish but remained unaffected in fed fish. HEA exposure at normal salinity (32 ppt) and at reduced salinities (20 ppt and 10 ppt) increased ammonia accumulation significantly (84 h–180 h) in both feeding regimes which was associated with an increment of H₂O₂ and MDA contents. Unlike in fasted fish, H₂O₂ and MDA levels in fed fish were restored to control levels (84 h–180 h); with a concomitant increase in superoxide dismutase (SOD), catalase (CAT), components of the glutathione redox cycle (reduced glutathione, glutathione peroxidase and glutathione reductase), ascorbate peroxidase (APX) activity and reduced ascorbate (ASC) content. On the contrary, fasted fish could not activate many of these protective systems and rely mainly on CAT and ASC dependent pathways as antioxidative sentinels. The present findings exemplify that in fed fish single factors and a combination of HEA exposure and reduced seawater salinities (upto 10 ppt) were insufficient to cause oxidative damage due to the highly competent antioxidant system compared to fasted fish. However, the impact of HEA exposure at a hypo-saline environment (2.5 ppt) also defied antioxidant defence system in fed fish, suggesting this combined factor is beyond the tolerance range for both feeding groups. Overall, our results indicate that the oxidative stress mediated by the experimental conditions were exacerbated during starvation, and also suggest that feed deprivation particularly at reduced seawater salinities can instigate fish more susceptible to ammonia toxicity.

Vigorous exercise training improves reactivity of cerebral arterioles and reduces brain injury following transient focal ischemia

OBJECTIVE

Our objective was to examine whether vigorous exercise training (VExT) could influence nitric oxide synthase (NOS)-dependent vasodilation and transient focal ischemia-induced brain injury. Rats were divided into sedentary (SED) or VExT groups.

MATERIALS AND METHODS

Exercise was carried out 5 days/week for a period of 8-10 weeks. First, we measured responses of pial arterioles to an eNOS-dependent (ADP), an nNOS-dependent (NMDA) and a NOS-independent (nitroglycerin) agonist in SED and VExT rats. Second, we measured infarct volume in SED and VExT rats following middle cerebral artery occlusion (MCAO). Third, we measured superoxide levels in brain tissue of SED and VExT rats under basal and stimulated conditions.

RESULTS

We found that eNOS- and nNOS-dependent, but not NOS-independent vasodilation, was increased in VExT compared to SED rats, and this could be inhibited with L-NMMA in both groups. In addition, we found that VExT reduced infarct volume following MCAO when compared to SED rats. Further, superoxide levels were similar in brain tissue from SED and VExT rats under basal and stimulated conditions.

CONCLUSIONS

We suggest that VExT potentiates NOS-dependent vascular reactivity and reduces infarct volume following MCAO via a mechanism that appears to be independent of oxidative stress, but presumably related to an increase in the contribution of nitric oxide.

Soybean flour induces a greater increase of the antioxidant defenses in rats fed with a normocaloric diet compared with a hypercaloric diet

BACKGROUND

Soybeans, due to their antioxidant properties, present beneficial health effects. The objective was to evaluate if replacing casein with soy flour, modifies antioxidant defenses in rat liver, compared to animals that continued being fed with casein based diets (normocaloric and hypercaloric).

RESULTS

Four groups of rats were used: CC (control casein), CS (control soy), HC (hypercaloric casein) and HS (hypercaloric soy). Malondialdehyde, in serum and liver, did not present differences. In liver, when comparing CS vs. CC: increased superoxide dismutase 1 (P < 0.001), catalase (P < 0.01) and glutathione reductase (P < 0.05) activities, the total glutathione (P < 0.001) and reduced glutathione (P < 0.05) content and decreased oxidized glutathione content (P < 0.05). In HS vs. HC: increased carbonyl groups (P < 0.01) and superoxide dismutase 1 activity (P < 0.05), and decreased glutathione peroxidase activity (P < 0.01), total glutathione (P < 0.05) and oxidized glutathione content (P < 0.001). In HS vs. CS: decreased glutathione reductase activity (P < 0.01), total glutathione (P < 0.001) and reduced glutathione (P < 0.01) content, and increased oxidized glutathione content (P < 0.05).

CONCLUSION

Replacing casein by soybean flour improves antioxidant defenses, mainly in normocaloric diets.

Free radicals and antioxidants in cardiovascular diseases

It has been demonstrated that redox homeostasis is important in the pathophysiology of several human diseases, including cardiovascular diseases. In this respect, genetic polymorphism, nutritional and environmental factors, age, lifestyle and physical activity may account for variable antioxidant defenses, which may be more or less effective at counteracting oxidative damage. Since accumulating oxidative damage may be associated with several pathologic conditions, including different cardiovascular diseases, prevention of oxidative stress appears to be a promising approach to improve such diseases. Exercise training, diets rich in antioxidants and a good control of blood glucose and lipid levels help to strengthen the physiologic antioxidant defense system, perhaps coupled to drugs capable of increasing the nitric oxide bioavailability and decreasing superoxide production. Within the next few years other therapeutic approaches will be available, such as gene therapy, which will prove to be even more effective but devoid of several important systemic side effects.

Regulation Systems of Bacteria such as Escherichia coli in Response to Nutrient Limitation and Environmental Stresses

An overview was made to understand the regulation system of a bacterial cell such as Escherichia coli in response to nutrient limitation such as carbon, nitrogen, phosphate, sulfur, ion sources, and environmental stresses such as oxidative stress, acid shock, heat shock, and solvent stresses. It is quite important to understand how the cell detects environmental signals, integrate such information, and how the cell system is regulated. As for catabolite regulation, F1,6B P (FDP), PEP, and PYR play important roles in enzyme level regulation together with transcriptional regulation by such transcription factors as Cra, Fis, CsrA, and cAMP-Crp. αKG plays an important role in the coordinated control between carbon (C)- and nitrogen (N)-limitations, where αKG inhibits enzyme I (EI) of phosphotransferase system (PTS), thus regulating the glucose uptake rate in accordance with N level. As such, multiple regulation systems are co-ordinated for the cell synthesis and energy generation against nutrient limitations and environmental stresses. As for oxidative stress, the TCA cycle both generates and scavenges the reactive oxygen species (ROSs), where NADPH produced at ICDH and the oxidative pentose phosphate pathways play an important role in coping with oxidative stress. Solvent resistant mechanism was also considered for the stresses caused by biofuels and biochemicals production in the cell.

Oxidative stress in aging--matters of the heart and mind

Oxidative damage is considered to be the primary cause of several aging associated disease pathologies. Cumulative oxidative damage tends to be pervasive among cellular macromolecules, impacting proteins, lipids, RNA and DNA of cells. At a systemic level, events subsequent to oxidative damage induce an inflammatory response to sites of oxidative damage, often contributing to additional oxidative stress. At a cellular level, oxidative damage to mitochondria results in acidification of the cytoplasm and release of cytochrome c, causing apoptosis. This review summarizes findings in the literature on oxidative stress and consequent damage on cells and tissues of the cardiovascular system and the central nervous system, with a focus on aging-related diseases that have well-documented evidence of oxidative damage in initiation and/or progression of the disease. The current understanding of the cellular mechanisms with a focus on macromolecular damage, impacted cellular pathways and gross morphological changes associated with oxidative damage is also reviewed. Additionally, the impact of calorific restriction with its profound impact on cardiovascular and neuronal aging is addressed.

Influence of exercise training on ischemic brain injury in type 1 diabetic rats

While exercise training (ExT) appears to influence cerebrovascular function during type 1 diabetes (T1D), it is not clear whether this beneficial effect extends to protecting the brain from ischemia-induced brain injury. Thus our goal was to examine whether modest ExT could influence transient focal ischemia-induced brain injury along with nitric oxide synthase (NOS)-dependent dilation of cerebral (pial) arterioles during T1D. Sprague-Dawley rats were divided into four groups: nondiabetic sedentary, nondiabetic ExT, diabetic (streptozotocin; 50 mg/kg ip) sedentary, and diabetic ExT. In the first series of studies, we measured infarct volume in all groups of rats following right MCA occlusion for 2 h, followed by 24 h of reperfusion. In a second series of studies, a craniotomy was performed over the parietal cortex, and we measured responses of pial arterioles to an endothelial NOS (eNOS)-dependent, a neuronal NOS (nNOS)-dependent, and a NOS-independent agonist in all groups of rats. We found that sedentary diabetic rats had significantly larger total, cortical, and subcortical infarct volumes following ischemia-reperfusion than sedentary nondiabetic, nondiabetic ExT, and diabetic ExT rats. Infarct volumes were similar in sedentary nondiabetic, ExT nondiabetic, and ExT diabetic rats. In contrast, ExT did not alter infarct size in nondiabetic compared with sedentary nondiabetic rats. In addition, ExT diabetic rats had impaired eNOS- and nNOS-dependent, but not NOS-independent, vasodilation that was restored by ExT. Thus ExT of T1D rats lessened ischemic brain injury following middle cerebral artery occlusion and restored impaired eNOS- and nNOS-dependent vascular function. Since the incidence of ischemic stroke is increased during T1D, we suggest that our finding are significant in that modest ExT may be a viable preventative therapeutic approach to lessen ischemia-induced brain injury that may occur in T1D subjects.

Molecular characterization, expression, and functional analysis of two thioredoxins in the black rockfish (Sebastes schlegelii)

Thioredoxins (TRxs) are a family of small evolutionarily conserved proteins that are essential for the maintenance of cellular homeostasis. Two TRx homologue cDNAs were isolated from a black rockfish concanavalin A (Con A)/phorbol myristate acetate (PMA)-stimulated leucocyte cDNA library and named BrTPx1-1 and BrTPx1-2. As compared with other known TRx peptide sequences, the most conserved regions of both BrTRx1-1 and BrTRx1-2 peptides were found to be the redox-active site Trp-Cys-X-X-Cys (WCXXC). The TRx present in most species is a TRx1-2 protein with a Cys-Pro-Gly-Cys (CPGC) active site. However, in the larger 13 kDa BrTRx1-1 protein, a Cys-Pro-Pro-Cys (CPPC) active site was identified. Here, we report the identification of a new member of the TRx protein family from the teleost black rockfish, which defines a new subclass of 13-kDa TRx1-1 proteins. Phylogenetic analysis indicated that both BrTRx1-1 and BrTRx1-2 were grouped with other vertebrate TRx1 peptides. BrTRx1-1 expression was strongly induced in peripheral blood leucocytes (PBLs) 12-24 h following Con A/PMA stimulation, with peak expression at 24 h post-stimulation. BrTRx1-2 was induced in PBLs after stimulation with lipopolysaccharide (LPS), Con A/PMA, or poly I:C at 24 h. The BrTRx1-1 gene was predominantly expressed in the liver and gills, while BrTRx1-2 was expressed in PBLs and gills. After treatment with a high concentration (10 μg/mL) of rBrTRx1-1 or rBrTRx1-2, kidney leucocytes exhibited increased cell proliferation and viability under oxidative stress.

The effects of detraining on blood adipokines and antioxidant enzyme in Korean overweight children

The present study examined the change to clarify the effects of detraining on the concentration of lipid profiles, serum adipokines and antioxidant enzyme gene expression in Korean overweight children. The subjects were normal children (n = 19) and obese children (n = 20) who were further subdivided into the overweight training (OT) group (n = 10) and the overweight detraining (OD) group (n = 10). Maximal oxygen uptake (VO(2)max); body composition; lipid profiles (TG, TC); adipokines (adiponectin and leptin); antioxidants (blood and gene expressions SOD and GPX) were measured before, 12 weeks, and 24 weeks after the exercise program. Body mass index (BMI) and %fat were significantly higher in the OD group only. However, waist hip ration (WHR) and systolic blood pressure (SBP) were significantly decreased in the OT group. TG was significantly decreased in the OT group. There was a significant difference in TG level between the two groups. Besides, adiponectin was significantly increased in both the OT group and the OD group. Furthermore, leptin was significantly decreased in the OT group. There was a significant difference in leptin level between the two groups. In training groups, the expression of SOD was significantly increased after a 12- and 24-week period (p < 0.05). However, detraining group was significantly increased after a 12-week only (p < 0.05). In addition, GPX was significantly increased after a 24-week only in the training group (p < 0.05). Thus, detraining showed that negative effected on body composition and lipid profiles and maintained of uniform period on adipokines and antioxidant enzyme the protein and expression.

Chronic exercise preserves renal structure and hemodynamics in spontaneously hypertensive rats

AIMS

Exercise training (ExT) is a recommended adjunct to many pharmaceutical antihypertensive therapies. The effects of chronic ExT on the development of hypertension-induced renal injury remain unknown. We examined whether ExT would preserve renal hemodynamics and structure in the spontaneously hypertensive rat (SHR), and whether these effects were mediated by improved redox status and decreased inflammation. Normotensive WKY rats and SHR underwent moderate-intensity ExT for 16 weeks. One group of SHR animals was treated with hydralazine to investigate the pressure-dependent/independent effects of ExT. Acute renal clearance experiments were performed prior to sacrifice. Tissue free radical production rates were measured by electron paramagnetic resonance; gene and protein expression were measured by real time RT-PCR and Western blot or immunofluorescence, respectively. Plasma angiotensin II levels and kidney antioxidants were assessed. Training efficacy was assessed by citrate synthase activity assay in hind-limb muscle.

RESULTS

ExT delayed hypertension, prevented oxidative stress and inflammation, preserved antioxidant status, prevented an increase in circulating AngII levels, and preserved renal hemodynamics and structure in SHR. In addition, exercise-induced effects, at least, in part, were found to be pressure-independent.

INNOVATION

This study is the first to provide mechanistic evidence for the renoprotective benefits of ExT in a model of hypertension. Our results demonstrate that initiation of ExT in susceptible patients can delay the development of hypertension and provide renoprotection at the functional and ultrastructural level.

CONCLUSION

Chronic ExT preserves renal hemodynamics and structure in SHR; these effects are partially mediated by improved redox status and decreased inflammation.

Two superoxide dismutase (SOD) with different subcellular localizations involved in innate immunity in Crassostrea hongkongensis

SODs are ubiquitous metalloenzymes that can scavenge superoxides in response to various stresses. In the present study, full-length cDNAs of two SOD genes were isolated from Crassostrea hongkongensis (designated ChMnSOD and ChCuZnSOD). The cDNAs are 997 and 918 bp in length with ORFs of 675 and 468 bp (encoding 225 and 156 amino acids), respectively. Sequence analysis revealed a conserved Sod_Fe domain in ChMnSOD, and a Sod_Cu_Zn domain in ChCuZnSOD. Subcellular localization of ChMnSOD is mitochondrial while intracellular expression of ChCuZnSOD is detected. Although their expression overlaps in a wide range of tissues, ChMnSOD mRNA expression is high in gonad while ChCuZnSOD's is strong in adductor muscle. After infection by Vibrio alginolyticus, ChMnSOD mRNA was up-regulated 5 fold (p < 0.05) at 4 h, but returned to normal level 6 h post-infection. The expression of ChCuZnSOD gene showed a slight delay to the infection challenge and was elevated roughly 4 fold after 8 h (p < 0.05), returning to normal at 12 h post-infection. The elevated transcript levels of the two SOD genes in response to V. alginolyticus infection highlights their important functions in eliminating toxic reactive oxygen species (ROS) and protecting organisms from bacterial invasion in C. hongkongensis.

Exercise training normalizes impaired NOS-dependent responses of cerebral arterioles in type 1 diabetic rats

Our goal was to examine whether exercise training (ExT) could normalize impaired nitric oxide synthase (NOS)-dependent dilation of cerebral (pial) arterioles during type 1 diabetes (T1D). We measured the in vivo diameter of pial arterioles in sedentary and exercised nondiabetic and diabetic rats in response to an endothelial NOS (eNOS)-dependent (ADP), an neuronal NOS (nNOS)-dependent [N-methyl-D-aspartate (NMDA)], and a NOS-independent (nitroglycerin) agonist. In addition, we measured superoxide anion levels in brain tissue under basal conditions in sedentary and exercised nondiabetic and diabetic rats. Furthermore, we used Western blot analysis to determine eNOS and nNOS protein levels in cerebral vessels/brain tissue in sedentary and exercised nondiabetic and diabetic rats. We found that ADP and NMDA produced a dilation of pial arterioles that was similar in sedentary and exercised nondiabetic rats. In contrast, ADP and NMDA produced only minimal vasodilation in sedentary diabetic rats. ExT restored impaired ADP- and NMDA-induced vasodilation observed in diabetic rats to that observed in nondiabetics. Nitroglycerin produced a dilation of pial arterioles that was similar in sedentary and exercised nondiabetic and diabetic rats. Superoxide levels in cortex tissue were similar in sedentary and exercised nondiabetic rats, were increased in sedentary diabetic rats, and were normalized by ExT in diabetic rats. Finally, we found that eNOS protein was increased in diabetic rats and further increased by ExT and that nNOS protein was not influenced by T1D but was increased by ExT. We conclude that ExT can alleviate impaired eNOS- and nNOS-dependent responses of pial arterioles during T1D.

Brown adipose tissue redox status in response to dietary-induced obesity-associated oxidative stress in male and female rats

Obesity is linked to systemic oxidative stress and, although brown adipose tissue (BAT) plays a crucial role in energy balance, BAT redox status effects on obesity have not been studied previously. Female rats exhibit a greater BAT thermogenic capacity, attributed to enhanced mitochondrial differentiation, than males. The aim of this study was to investigate whether the mitochondrial sexual dimorphism is related to differences in BAT redox status and to assess its role in the regulation of body weight gain in response to chronic high fat diet (HFD) feeding. Ten-week-old Wistar rats of both genders were fed a pelleted control diet or HFD for 26 weeks. Although mitochondria of female rats produced higher levels of hydrogen peroxide than those of males, females exhibited lower oxidative damage, attributed to greater glutathione peroxidase activity and higher glutathione content. In response to HFD, body weight increased markedly in females, but oxidative capacity increased only in males, thus maintaining improved BAT redox status compared with females. In conclusion, the sexual dimorphism in BAT redox status found in control animals is attenuated by the HFD. The enhanced oxidative capacity of HFD males can be related to their greater resistance to body weight gain.

Effects of coenzyme Q10 supplementation on activities of selected antioxidative enzymes and lipid peroxidation in hypertensive patients treated with indapamide. A pilot study

INTRODUCTION

An increase in oxidative stress is strongly documented in hypertensive patients. In blood vessels, oxidative stress increases the production of superoxide anion (O(2) (•-)) that reacts with nitric oxide (NO) and impairs the ability of endothelium to relax. Many reports indicate a beneficial effect of coenzyme Q10 (CoQ) in hypertension. Coenzyme Q10 therapy may lower O(2) (•-) and thus decrease the complications associated with hypertension. The aim of our study was to evaluate the effects of CoQ supplementation on antioxidative enzyme activities and lipid peroxidation in elderly hypertensive patients.

MATERIAL AND METHODS

We determined the activities of superoxide dismutase (SOD-1) and glutathione peroxidase (GSH-Px) and the concentration of malondialdehyde (MDA) in erythrocytes of 27 elderly (mean age 72.5 ±6.1 year) hypertensive patients treated with indapamide at baseline and after 12 weeks of CoQ supplementation (60 mg twice a day) in comparison with 30 healthy elderly volunteers (mean age 76.8 ±8.5 year).

RESULTS

Decrease of SOD-1 (p < 0.001) and insignificant reduction of GSH-Px activities and increase of MDA (p < 0.001) level were observed in hypertensive patients in comparison to healthy volunteers before supplementation. Coenzyme Q10 administration resulted in a significant increase only in SOD-1 activity (p < 0.001).

CONCLUSIONS

The present study indicates that CoQ improves the most important component of the antioxidant defence system - SOD-1, which is responsible for O(2) (•-) scavenging. Coenzyme Q10 may be used as an additional therapeutic agent for prophylaxis and treatment of hypertension in elderly patients.

Association between manganese superoxide dismutase (MnSOD) gene polymorphism and elderly obesity

Evidence suggests an association between obesity and oxidative stress caused by superoxide production. Since the dismutation of superoxide is catalyzed by superoxide dismutase enzymes, we tested the association between obesity and Ala16Val manganese-dependent superoxide dismutase gene (MnSOD) polymorphism. We analyzed 815 free-living community subjects (> or =60 years old) grouped into subjects who were either obese (BMI > or = 30 kg/m(2)) or non-obese (BMI < 25 kg/m(2)). Additionally, we investigated the possible interaction between the Ala16Val MnSOD gene polymorphism and obesity in the modulation of biochemical and nutritional variables. We found a positive association between MnSOD polymorphism and obesity, since higher VV frequency (28.2%) was observed in the obese group (P = 0.002, odds ratio 1.949, 95% CI: 1.223-3.008). This result was independent of sex, age, diabetes, dyslipidemia, hypertension, and metabolic syndrome. A possible biological explanation of the association described here could be a chronic state of superoxide enzyme imbalance present in VV carriers, which could affect differential metabolic pathways contributing to the obese state.

Antioxidative effects of melatonin administration in elderly primary essential hypertension patients

The imbalance of the redox state of the aging organism may be involved in the development of primary essential hypertension. Melatonin, a potent antioxidant agent, was found to exert a hypotensive effect and improve the function of the cardiovascular system. The aim of this study was to determine the influence of melatonin supplementation on oxidative stress parameters in elderly primary essential hypertensive (EH) patients, controlled by a diuretic (indapamide) monotherapy. The levels of malondialdehyde (MDA) and reduced glutathione (GSH), activities of Cu-Zn superoxide dismutase (SOD-1), catalase (CAT) and glutathione peroxidase (GSH-Px) in erythrocytes, the plasma level of nitrate/nitrite, the content of carbonyl groups of plasma proteins and morning melatonin levels in the serum of 17 elderly EH patients were determined at the baseline and after the 15th and 30th days of melatonin supplementation (5 mg daily). Melatonin administration resulted in a significant increase in the morning melatonin concentration, SOD-1 and CAT activities, and a reduction in the MDA level. Statistically significant alterations in the levels of GSH, nitrate/nitrite and carbonyl groups and the activity of GSH-Px were not observed. These results indicate an improvement in the antioxidative defense of the organism by melatonin supplementation in the examined group and may suggest melatonin supplementation as an additional treatment supporting hypotensive therapy in elderly EH patients.

Oxidative stress and metabolism at rest and during exercise in persons with Down syndrome

BACKGROUND

Down syndrome (DS) is a risk factor for metabolic syndrome and cardiovascular disease. The greater oxidative stress described in DS can increase this risk owing to its potential deleterious effects on insulin sensitivity. We hypothesized that metabolic syndrome or its markers, at rest and during exercise, are more pronounced in young adults with DS.

DESIGN

The study design is that of a controlled study.

METHODS

Thirteen physically active young adults with DS, after overnight polysomnography, plasma-lipid profile, and insulin-resistance [Homeostasis Model Assessment Insulin Resistance (HOMA-IR)] assessments, underwent a submaximal progressive treadmill exercise (10 min at 30 and 50%, and 20 min at 75% of V O2max), allowing for maximal fat-oxidation rate and blood-oxidative stress determinations. They were compared with 15 healthy control participants (C).

RESULTS

V O2max of DS participants was lower than that of C (60.8+/-2.4 versus 44.4+/-3.3 ml/kg/min; P<0.001) but was close to the predicted value (95+/-6%). In DS participants, as expected, oxidative stress was greater than in C (+15%; P<0.001) at rest and all through the exercise protocol. Although a greater fat mass (DS: 19.9+/-1.3%; C: 13.5+/-0.9%; P<0.001), and a lower insulin sensitivity (HOMA-IR in DS: 1.09+/-0.16; in C: 0.64+/-0.13; P<0.05) was observed for DS participants, a metabolic syndrome could not be shown. Maximal fat-oxidation rate was lower in DS participants (394.2+/-69.9 versus 486.1+/-134.8 mg/min in C; P<0.01), but it was in the normal range.

CONCLUSION

Despite greater oxidative stress and lower insulin sensitivity, the DS group involved in our study did not display clear metabolic abnormalities. The young age and lifestyle of this group might, partially, have accounted for this apparently healthy metabolic status.

Angiotensin II regulates cardiac hypertrophy via oxidative stress but not antioxidant enzyme activities in experimental renovascular hypertension

The aim of this study was to provide new insights into the role of angiotensin II and arterial pressure in the regulation of antioxidant enzyme activities in a renovascular model of cardiac hypertrophy. For this purpose, aortic coarcted rats were treated with losartan or minoxidil for 7 days. Angiotensin II induced cardiac hypertrophy and oxidative stress via Nox4, p22(phox) and p47(phox), which are components of the NAD(P)H oxidase. Antioxidant enzymes were regulated by arterial pressure and were not implicated in cardiac hypertrophy. Heme oxygenase-1, the rate-limiting enzyme in heme catabolism, behaved as a catalase and glutathione peroxidase, and is regulated by arterial pressure. In summary, the present report indicates that cardiac hypertrophy, induced by renovascular hypertension, depends on angiotensin II through reactive oxygen species and is not prevented by the action of antioxidant enzymes.

Chronic quercetin ingestion and exercise-induced oxidative damage and inflammation

Quercetin is a flavonoid compound that has been demonstrated to be a potent antioxidant in vitro. The objective of this study was to evaluate if quercetin ingestion would increase plasma antioxidant measures and attenuate increases in exercise-induced oxidative damage. Forty athletes were recruited and randomized to quercetin or placebo. Subjects consumed 1000 mg quercetin or placebo each day for 6 weeks before and during 3 d of cycling at 57% work maximum for 3 h. Blood was collected before and immediately after exercise each day, and analyzed for F2-isoprostanes, nitrite, ferric-reducing ability of plasma, trolox equivalent antioxidant capacity, and C-reactive protein. Statistical analyses involved a 2 (treatment) × 6 (times) repeated measures analysis of variance to test main effects. F2-isoprostanes, nitrite, ferric-reducing ability of plasma, trolox equivalent antioxidant capacity, and C-reactive protein were significantly elevated as a result of exercise, but no group effects were found. Despite previous data demonstrating potent antioxidant actions of quercetin in vitro, this study indicates that this effect is absent in vivo and that chronic quercetin ingestion does not exert protection from exercise-induced oxidative stress and inflammation.

The tricarboxylic acid cycle, an ancient metabolic network with a novel twist

The tricarboxylic acid (TCA) cycle is an essential metabolic network in all oxidative organisms and provides precursors for anabolic processes and reducing factors (NADH and FADH₂) that drive the generation of energy. Here, we show that this metabolic network is also an integral part of the oxidative defence machinery in living organisms and α-ketoglutarate (KG) is a key participant in the detoxification of reactive oxygen species (ROS). Its utilization as an anti-oxidant can effectively diminish ROS and curtail the formation of NADH, a situation that further impedes the release of ROS via oxidative phosphorylation. Thus, the increased production of KG mediated by NADP-dependent isocitrate dehydrogenase (NADP-ICDH) and its decreased utilization via the TCA cycle confer a unique strategy to modulate the cellular redox environment. Activities of α-ketoglutarate dehydrogenase (KGDH), NAD-dependent isocitrate dehydrogenase (NAD-ICDH), and succinate dehydrogenase (SDH) were sharply diminished in the cellular systems exposed to conditions conducive to oxidative stress. These findings uncover an intricate link between TCA cycle and ROS homeostasis and may help explain the ineffective TCA cycle that characterizes various pathological conditions and ageing.

Leptin, superoxide dismutase, and weight loss: initial leptin predicts weight loss

OBJECTIVE

Our goal was to study how plasma leptin concentration, superoxide dismutase (SOD) activity, and weight loss are related in obese adults.

RESEARCH METHODS AND PROCEDURES

Serum leptin concentration, SOD activities, general biochemical data, and body composition measurements were obtained for 62 overweight and obese subjects before and after an 8-week body weight reduction (BWR) regimen. The subjects were on dietary control, performed moderate aerobic and strength training exercises, and attended educational lectures.

RESULTS

The measurement results indicated that the following criteria were significantly reduced: body weight [84.4 +/- 17.0 vs. 79.3 +/- 16.1 (standard error) kg, p < 0.001]; BMI (31.5 +/- 4.3 vs. 29.4 +/- 4.2 kg/m(2), p < 0.001), and fat mass (33.3 +/- 10.0 vs. 29.8 +/- 10.4 kg, p < 0.001). Plasma leptin levels also significantly decreased from 31.5 +/- 17.6 to 26.5 +/- 17.2 ng/mL (p < 0.001). Additionally, SOD activity was significantly increased from 261.4 +/- 66.0 to 302.7 +/- 30.9 U/mL (p < 0.001). Based on linear regression analysis results, a 3.78- to 8.13-kg reduction in weight can be expected after the 8-week BWR regimen when initial leptin concentration was 5 to 30 ng/mL.

DISCUSSION

We found that an 8-week exercise and diet program was effective in reducing weight and fat mass and, notably, had further beneficial effects on leptin resistance and SOD activity. Additionally, this study demonstrated that initial plasma leptin concentration may be used as a predictor for weight loss outcome.

Effects of endurance training and acute exhaustive exercise on antioxidant defense mechanisms in rat heart

We investigated whether 8-week treadmill training strengthens antioxidant enzymes and decreases lipid peroxidation in rat heart. The effects of acute exhaustive exercise were also investigated. Male rats (Rattus norvegicus, Sprague-Dawley strain) were divided into trained and untrained groups. Both groups were further divided equally into two groups where the rats were studied at rest and immediately after exhaustive exercise. Endurance training consisted of treadmill running 1.5 h day(-1), 5 days week(-1) for 8 weeks. For acute exhaustive exercise, graded treadmill running was conducted. Malondialdehyde level in heart tissue was not affected by acute exhaustive exercise in untrained and trained rats. The activities of glutathione peroxidase and glutathione reductase enzymes decreased by both acute exercise and training. Glutathione S-transferase and catalase activities were not affected. Total and non-enzymatic superoxide scavenger activities were not affected either. Superoxide dismutase activity decreased by acute exercise in untrained rats; however, this decrease was not observed in trained rats. Our results suggested that rat heart has sufficient antioxidant enzyme capacity to cope with exercise-induced oxidative stress, and adaptive changes in antioxidant enzymes due to endurance training are limited.

Exercise, oxidative stress and risk of cardiovascular disease in the elderly. Protective role of antioxidant functional foods

Free radicals and oxidative stress are involved in the pathogenic mechanisms of cardiovascular disease (CVD), diabetes and cancer. Exercise is a useful strategy for preventing CVD but in elderly persons it can enhance oxidative stress, which is why some studies recommend antioxidant supplementation for exercising elderly subjects. This intervention study was performed on 320 elderly subjects following a Geriatric Revitalization Program (GEREPRO) to maintain physical health and reduce CVD risk. GEREPRO was based on regular exercise concurrent with a nutritional antioxidant treatment based on daily intake of a functional antioxidant food, Biofrutas. Sustained exercise (10 months, 3 sessions/week) significantly increased cardiorespiratory fitness and plasma HDL-cholesterol; it reduced some predictors of cardiovascular risk (arterial pressure, LDL-cholesterol, total cholesterol/LDL-C, LDL-C/HDL-C), but significantly enhanced some biomarkers of oxidative stress. Concurrent antioxidant supplementation did not produce any ergogenic effects but, meaningfully, enhanced some positive effects of exercise on physical health and the CDV risk index, and it totally prevented the exercise-induced oxidative stress. Our results show that regular and moderate exercise improves cardiorespiratory function and reduces CVD risk in elderly people, while concurrent antioxidant supplementation modulates oxidative insult during exercise in the elderly and enhances the beneficial effects of exercise.

Exercise and endothelial function: role of endothelium-derived nitric oxide and oxidative stress in healthy subjects and hypertensive patients

Recent epidemiologic studies have shown that aerobic exercise, one of lifestyle modifications, reduces cardiovascular morbidity and mortality in the general population. However, the mechanisms underlying the anti-atherogenic and anti-hypertensive effects of exercise remain unclear. Hypertension is associated with alteration in endothelial function mediated through reduced nitric oxide (NO) bioavailability. Endothelial dysfunction is an early feature of atherosclerosis and vascular diseases in humans. Exercise training has been shown to improve endothelial function in animal models of hypertension and in patients with essential hypertension. These findings suggest that endothelial dysfunction in hypertension is reversible. Lifestyle modifications including exercise are expected to prevent cardiovascular complications through an augmentation of endothelial function in hypertensive patients. It is thought that exercise increases NO production and decreases NO inactivation, leading to an increase in NO bioavailability. In this review, we will focus on recent findings and on possible mechanisms underlying the beneficial effects of exercise on endothelial function in patients with hypertension.